I am trying to get the right answer on a problem I am experiencing with my 2000 540. Aside from the service engine soon light always being on, The computer gives me a code of 26 and 27, indicating that the car is too lean +22-25% each bank, pretty much at the max of the spectrum. I purchased the car on July 21st, this year. It is a US spec but I bought it in Germany and I currently live in Italy. I had the car checked out before I bought it, and at the time it looked like it was the 4 O2 sensors, of which 2 were replaced on the spot. The German mechanic reset the light, but 45 minutes later, it came back on. The car drove great all the way back to Italy (over 600 miles). It still drives fine, though I think it could be more responsive when you really give it gas. I have read many forums about this, but still don't really have an answer. I know of a BMW master mechanic in VA who has family over here and is coming over soon. He wants to replace the valve seals and a valve in the crank shaft; he claims there is a common problem with a small air leak from somewhere near the crank shaft, which causes the computer to adjust to compensate, resulting in leaning out. He would bring the parts with him (about $1200.00 worth) and said it would take between 12-15 hrs of labor.
The German mechanic said that he did not have the time to get and install the other two sensors prior to me leaving for Italy, and that the light would likely come on again. He said that everything was fine with the car and that it was turning over (exhaust & firing) perfectly.
I have had other mechanics tell me that the one guy wanting to redo the entire crankshaft and seals is likely overkill or not even the problem...
Oh, yeah, anyone know what code 141 refers to?